Vol 18, No 2 (2018)
- Year: 2018
- Articles: 8
- URL: https://ered.pstu.ru/index.php/geo/issue/view/105
Abstract
The paper is devoted to the urgent problem of studying the prospects of the oil and gas potential of Riphean-Vendian sediments of poorly studied areas such as northeastern regions of the Volga-Ural oil and gas province. The paper presents the characteristic of the lithological and stratigraphic features of the structure of Riphean and Vendian deposits in the northeastern part of the Volga-Ural oil and gas province. Particular attention is paid to the basin modeling of well sections that did not fully passed through the Riphean-Vendian complex of rocks.That allows to predict oil and gas generation processes. During the research sections of three wells were modelled. Wells Keltmenskaya-1, Krasnovisherskaya-18, Borovitskaya-624 revealed Upper Proterozoic rocks in the north-east of the Perm region and the Komi Republic. Procedure features of the used software systems, phasing of the research, including gathering and input of initial data, processing of parameters, calculation and calibration of models are given. Certain challenges associated with modeling the conditions of oil and gas formation and oil and gas accumulation of Riphean and Vendian sediments of this territory are associated with insufficient information on the structure and composition of sediments, incomplete drilling of ancient sediments in wells and inconsistent geophysical data. In addition, the complexity of the reconstruction lies in the lack of information about geothermal conditions of sections, numerous interruptions in sedimentation and erosion of sediments. According to simulation results, most of the Riphean-Vendian sedimentary section is located in the main zone of oil generation. The research conducted allowed the authors to conclude that there are increased prospects to discover oil hydrocarbons in a wide range of depths in the areas where the Krasnovisherskaya-18 and Borovitskaya-624 wells are drilled. There is a little likelihood that gaseous hydrocarbons can be found in the section. Conducted research and obtained results pose a problem for the development of geological exploration in the poorly studied areas of the northeast of the Volga-Ural oil and gas province. First of all, that corresponds to reference-parametric drilling together with the zonal-regional geophysical studies.
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Abstract
The paper discusses the effect of high pressures on adsorption of inorganic ions (KCl), methylene blue and petroleum products (engine oil, transmission fluid, diesel fuel) by samples of montmorillonite and kaolinite. The relationship between the value of the applied pressure (in the range from 0 to 700 MPa), fractional composition, specific surface and the microstructure of mineral particles was revealed. During the study, dynamics of changes in the content of the clay, dust and sand fractions in the clays under study was noted. It is established that an increase in clay compression to 700 MPa leads to a decrease in the content of clay fractions and an increase in the fraction of the dust fraction. Changes in the fractional composition occur more intensively in kaolinite clay than in montmorillonite clay. The pressure intervals were determined according to the intensity of the formation of the fractional composition of clays 0-200 and 200-700 MPa. Adsorption parameters of clays are determined. According to potentiometric measurements, it has been established that the ion-exchange capacity is higher in montmorillonite than in kaolinite with in respect to cations. The magnitude of kaolinite adsorption with respect to methylene blue decreases to a pressure of 200 MPa, which is caused by the content of the clay fraction, does not change significantly at pressures of 200-700 MPa. The adsorption rate of montmorillonite has a general tendency to increase. Adsorption indicators of clays with respect to methylene blue allow predicting the sorption capacity of the studied materials to petroleum products.
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Abstract
Nowdays, the area of possible application of hydrocarbon-based muds (HCBM) is significantly expanding in the foreign and domestic practice of well construction. There is a lot of examples of successful use of HCBM when drilling complex wells in various geological conditions. There is a negative experience that indicates that the selected composition and technological properties of the HCBM did not fully meet geological conditions of drilling. In particular, there are cases when wellbore was not stable, as well as the failure to achieve the planned production rate due to the low quality of reservoir drilling. In order to increase the effectiveness of HCBM use, it is important to develop criteria for assessing their quality depending on geological conditions of use, which allow for the operational control of the quality of a mud in field conditions. Based on many years of experience of HCBM application, an algorithm is proposed for selecting the quality criteria for this type of solution, depending on the geological conditions of use. Requirements for a HCBM during the drilling of high deviation wells, including intervals of unstable terrigenous deposits under high formation temperatures are considered. Criteria for assessing the quality of the initial opening of productive layers are proposed. Criteria presented in the paper for assessing the quality of the HCBM will be useful for specialists in the field of drilling and production who are involved in the design and development of drilling fluids, including shale oil and gas deposits.
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Abstract
The paper presents the results of the analysis of the efficiency of improved oil recovery (IOR) methods designed to restore and increase the productivity of wells of Kashirskiy and Podolskiy reservoirs of the certain Perm region oil field. Indirect evidences prove that the carbonate reservoir of the formations exhibits fracture-pore-type reservoir properties, which affects the productivity of wells and results of IOR methods. Comparative analysis of the efficiency of IOR methods implemented on production wells poined out on higher values for proppant hydraulic fracturing (HF). The increment in well production oil rate after HF increases with an increase in the specific consumption of proppant. The calculations are performed according to the wave acoustic cross-dipole logging (cross-dipole sonic). According to the results of studies and calculations, the profile of horizontal stresses in the reservoir was constructed, the values of bottomhole pressure at which the closure of the fracture occurs in individual layers are substantiated. A retrospective design of the main HF was performed for a certain well. It is showed that the height of fracture development is limited by dense barriers above and below the perforation interval, while the part of the fracture formed is not packed with proppant. Proppant HF is accompanied by a significant increase in well water-cut after IOR methods implementation, the nature of which changes in subsequent periods indicates a high probability of involvment of formation drainage through a fractured interbeds with low natural oil saturation to the process. The analysis of the results of IOR methods, well logging data, taking into account the built retrospective design of the main HF, leads to the conclusion that it is necessary to optimize the technological parameters while designing the HF for production wells of the Kashirskiy and Podolskiy reservoirs of the certain Perm region oil fields That is controlled by increasing the specific consumption of proppant, reducing the polymer load and the share of the buffer stage of the main HF.
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Abstract
Development of fracture-porous reservoirs can be followed by breakthroughs of water injected into reservoirs through the system of cracks to production wells. This process can reduce the coverage of reservoir by sweeping, which will ultimately lead to a decrease in oil recovery factor. In order to perform a more effective fractured-porous reservoir flooding it is possible to use various methods associated with the injection of gel and sediment-forming agents, the use of wave technologies etc. The paper considers the formation with high-viscosity oil and fractured-porous reservoir. It is observed that water cut increase faster than oil recovery. The authors of the paper propose to use the wave effect associated with the stops of both injection and production wells. Shut-off and shut-in time of each well should be selected based on the parameters of the bottomhole zone. The specific value of the end time of the interaction of blocks and fractures when the pressure changes at the points of the reservoir can be roughly estimated from the beginning of the straight section of the pressure build-up curve in the fracture-porous reservoir. For the selected formation reservoir time of the end of the interaction between fractures and blocks with pressure changes was determined. Various options for implementation were proposed. Process impact modelling was performed using the Tempest More software package. According to the results of the simulation, it can be noted that the wave phenomenon is effective in terms of water cut reduction. Neverthelles, there are losses in oil production with long periods of shut-off of the wells. It should be noted that the time of interaction between fractures and blocks substantially depends on the permeability of the bottomhole zone; the higher the permeability the lower the time. It was also found that a variable frequency wave results in a greater effect.
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Abstract
The effect of water injection into a reservoir on oil production for Tournaisian deposits of the Sosnovskoe gas-oil field is evaluated. Statistical methods such as correlation, regression and stepwise discriminant analysis were used. Data on monthly and cumulative oil production, on amount of water injected into the reservoir from four injection and twelve production wells was used. Based on the data, studies have been performed to assess the effect of the volume of monthly water injection into the reservoir on monthly oil production, provided that each injection well affects only nearby producing wells. It was explained why there was no correlation between the parameters of monthly injection and monthly oil production. Then, in order to evaluate the efficiency of water injection into the reservoir, it was decided to use the data from the accumulated volume of water injection and the accumulated volume of oil production. It was found that there is a relationship between the parameters of the accumulated volume of water injection and the accumulated volume of oil production. The greater the accumulated volume of water injection, the greater the accumulated volume of oil production, but the gradients of increase for all wells are individual. Three areas were defined on the graphs. Relationships between the parameters have a high degree of linearity over a certain range. In order to establish the boundaries of those areas where the influence of the values of the accumulated volume of water injection on the accumulated volume of oil production is conditionally homogeneous, linear discriminant analysis was used. Results of the evaluation study show that water injection into the reservoir has a different degree of influence on the production wells. This analysis can be further applied to substantiate workovers and to identify hydrodynamic communication.
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Abstract
The paper is devoted to the development of a mathematical model for high-pressure hydro vortex inertial kinematic dust suppression. The suppression can significantly improve the efficiency of localization of man-made accidents and reduce the level of occupational pulmonary diseases. The dynamics of improving the technology and technical means of dust suppression in the mining and metallurgical complex of Russia shows their lack of effectiveness in ensuring sanitary conditions, especially in localization of dust mixture explosions. A further increase in the efficiency of coal mining and mineral processing is significantly limited by the imperfection of the technology for localizing and eliminating explosions of coal dust. The method of high-pressure hydro vortex dedusting is developed based on the theory of attached vortices. A mathematical model of hydro vortex inertial, kinematic heterocoagulation, which significantly increases the energy efficiency of dust suppression, is proposed. The graphical model of the interaction in the contact zone at the time of the collision in the liquid-solid system is refined. Stokes and Reynolds criteria equations are obtained with hydro vortex inertial orthokinetic heterocoagulation. An equation is obtained which allows to calculate the magnitude of the reduction in the required energy of the total absorption of dust particles as a function of the circulation of liquid droplets. Equations for calculation of effective wetting angle and the minimum diameter of absorbed dust particles are obtained as a function of the angular velocity of rotation of liquid droplets. It is shown that hydro vortex coagulation significantly reduces the size of the dispersed dust composition, water consumption, increasing the efficiency of dust suppression. A significant decrease in the size of the absorbed dust particles increases the efficiency of localization of coal dust explosions, reduces the incidence of silicosis and anthracosis. Certification tests using patent-protected vortex nozzles confirmed that there was a reduction in the minimum size of absorbed dust in four times, increase in dust collection efficiency of up to 99 %, reduce in water consumption by 20 % compared to classic high-pressure spray cleaning. The proposed technology of dust suppression can be used in mining companies when fine explosive dust mixtures are formed.
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Abstract
The paper presents results of the development of new scientific and methodological principles for assessing the fire safety of industrial premises evacuation routes. The basis of these principles is the scientific methodology for managing industrial safety, developed at the department of life safety at the Perm National Research Polytechnic University. Following is discussed in the paper: 1) method of modelling scenarios for fire break-out and development based on Ishikawa diagram, 2) mathematical model describing the stepwise process of fire break-out and development in accordance with diagram topology, 3) indicator of fire safety of evacuation routes, 4) model for estimating the probability of evacuation of people along through the evacuation routes, 5) model for estimating the probability of evacuation from the premises. The developments mentioned above took into account problematic issues related to the behavior of people during a fire (operational actions to turn off equipment or stop the process, speed of human response to fire signals and decision time), movement of people during evacuation inside confined or limited spaces (mines, containers, wells, vessels etc.), remoteness of workplaces from evacuation routes (scaffolding, crane tracks, work at height etc.), reliability of evacuation warning and control systems, absence of a clear algorithm for constructing fire scenarios. The areas of scientific research application are identified. A method for assessing the safety of evacuation routes in relation to fire extinguishing substances of automatic fire extinguishing units that pose a danger to human health is considered. Examples of the application of scientific developments in the assessment of evacuation routes fire safety and modelling a fire scenario at a specific production facility are given.
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